When the life did was actually originated in the earth and the rate of evolution and diversification of the earliest biota is still continued to be a very fascinating question before the astrobiologist and before the world scientific community. Similarly it is still unclear that when and how physiologically modern ecosystem based on oxygen producing photosynthesis really became established in the planet the earth [12]. The sole source of direct evidence relevant to such a question is plaeo-biologic record, contained in the rocks deposited during the Archieanon period of the earth history. It is almost >3500 MYR [Million years Ago]. The search for Archiean fossils was done with very difficulties. Few Archean sedimentary rocks had survived to the present time and paleobiological evidence in most of such rocks had been possible severely altered by metamorphism. In order to establish authenticity, arching microfossils, five principals criteria must be satisfied as per present authors. The positive microfossils I) must occur in rocks of known province ii) must be of established Archaean age by carbon dating iii) be demonstrably indigenous IV) synergic with primary deposition of enclosing rocks v) be assured biological origin by all microbiological, rRNA and DNA tests. All but a few of the microfossils like objects reported from Archean sediments have failed to meet one or more of these requirements. Other then filamentous Apex fossils, Archean Micro fossils record consist of two types of Cyano bacterium like filaments from~2750MYR old collnial uni- cell nonspecific bacterium like filaments ~3450MYR of Swazi land super group of south Africa. Apex filaments indicate that these primitive families of filamentous cyanobacteria were already highly diverse at the apex time. Although some cyanobacteria were capable of temporarily carrying out anoxic bacterial photosynthesis, oxygen producing photo autotrophy was then universal. These cyanobacteria had advanced level of physical evolution as early as ~3465MYR[William J Schoof- Science Vol260; P640; 1993]. Today all eukaryotes and other prokaryotes share a common ancestor with all the Archie bacteria whose members led pretyg exotic lives. The methane producing Methanogens, halophytes that dwell in salty environments and the eocytes. The rRNA study showed that Archie bacteria, an in other super class of prokaryotes, the eu-bacteria which include pathogen E.Coli are all closely related to each other and as a group they are very closely related to eu-karyotes. Archie-bacteria constitute one of the major evolutionary lineages on earth. Previously these prokaryotes were thought to predominate in only a few unusual and disparate niches, characterized by hyper saline, extremely hot or strictly anoxic conditions. In 1992, phylotypes of Archie bacteria had been detected in coastal and in subsurface of marine water also. Edward [Edward F Delong- Nature Vol371; P695; 1994] described high abundance of exceptionally archival in frigid marine surface water of Antarctica. Pre algae Archie constituted up to 34% of prokaryotic biomass in coastal Antarctica surface water and they were also abundant in a verity of other cold pelagic marine environment. These bacteria were typified by rRNA. Of al Antarctica bacteria sample collected in late austral water contained exceptionally high abundance of Archieal rRNA about18-30% of total pico plenkoton rRNA or 21-34% of total prokaryotic rRNA was archieal origin. Finding of Archie bacteria in these days was unexpected event and stands against Darwin’s theory of evolution. The Archie bacteria are live members of a group of microorganism that seem almost too Alien to have evolved on each. They resemble normal bacteria but are actually no more close to those bacteria than are to humans. The most obvious characteristics appear to be a taste for extreme temperature environment, which a large percentage of them inhibited. Various species live at temperature above the boiling point of water in lakes satire than the Dead Sea, in water more alkaline than household ammonia, more acidic environment than gastric juice and at consisting pressure of ocean depth. An Archie bacterium thus belongs to an independent kingdom, separate from eukariotes and also from other bacteria. The most dramatic selling of Arachae bacteria is found today in volcanic areas both on land and sea. On land, the hot gas and sulfurous fumes that leak out from earth produces Solfatara fields which can be found in such places as Iceland, Italy and yellow stones park. On the sea floor hydrothermal vents spew out sulfurous gas along with water at temperature that can reach hundred of degrees centigrade. Arachae bacteria is found to survive and grow at temperature up to 120 0c which is the highest temperature at which any organism not been ever found to survive. Methanopyrous a genus of Arachae bacteria family survive even at this temperature. Thermo toga Genus can survive up to 90 0c. Many of these thermophylic organisms live on organic materials combining carbon with hydrogen to form methane gas. Others get their energy by combining sulpher with hydrogen to form hydrogen sulphide. Arachae bacteria must have found some way to keep their DNA from unraveling. That might be possible by a type of his tone like protein discovered in microbes. When this protein is added to DNA in vitro, DNA can withstand temperature 30-40c higher than usual temperature The other possibility was that the double stranded DNA of arachaebacteria were twisted more strongly then the DNA of other creature evolved which would make it harder for the strand to separate.[Bhattacharya Pranab Kumar-2005] [ 1]
Probably about once in almost every decade a scientific discovery is reported that brings out passionate debate concerning the possible existence of extraterrestrial life, and panspermia theory [Bhattacharya-2009] [13], past or present. Nagy et al. (1961) [2] reported the occurrence of biogenic hydrocarbons in the Orgueil meteorite and then subsequently went on to describe possible relict microstructures that looked similar to microbial life forms on Earth (e.g. Nagy et al., 1963) [3]. Levin and Straat (1976) [4] reported the results of experiments performed during the Viking Mission to Mars that could be interpreted as possible evidence for extant microbial life in the outer space. Engel and Nagy (1982) [5] reported the occurrence of non-racemic amino acids in the Murchison meteorite (L-enantiomer excess) that could be interpreted as possible evidence for past extraterrestrial life. McKay et al. (1996) [ 6] reported possible evidence for fossil microbial life in the Martian meteorite ALH84001. The question was whether life started first in Rocks or in ocean?
For last decade, geologists also have looked at water droplets entangled in ancient Rocks — called fluid inclusions – of thousands years old trapped in the rocks found in death valley or saline valley of California USA and from Michigan, Kansas and Italy[ temperature in these locations are 130 degree Fahrenheit or more] and they wondered that microbes could be extracted from them. Fluid inclusions have been found inside salt crystals ranging in age from thousands to hundreds of millions years old. But there had always been a question about whether the organisms cultured from salt crystals are genuinely ancient material or of extraterrestrial origin or whether they are modern-day world contaminants,[science daily 22nd November-2010] and research on reviewed existing literature and they confirmed that microbes or allege DNA were over 100,000 years back and could survive as the conditions inside these water droplets are ideally suited to preserving their DNA
Richard Hoover[2011] [7] very recently had discovered evidence of microfossils similar to Cyanobacteria, as we discussed early in the article, in freshly fractured slices of the interior surfaces of the Alais, Ivuna, and Orgueil CI1 carbonaceous meteorites and in ALH 84001 meteorite based on Field Emission Scanning Electron Microscopy (FESEM) and other measures, This me- teorite seemed to have been ejected from the Planet Mars on earth, a few billion years ago and after a long and circuitous journey fell to Earth and remained buried in the Antarctic region for a few thousand years. Woo ! it proves pan-spermia theory and life in this planet appeared from Asteroids [1,13] Richard Hoover [7] has concluded they are indigenous to these meteors and are similar to trichomic cyanobacteria and other trichomic prokaryotes such as filamentous sulfur bacteria. He concludes these fossilized bacteria are not Earthly contaminants at all but are the fossilized remains of living organisms which lived in the parent bodies of these meteors, e.g. comets, moons, and other astral bodies. The implications are that life is everywhere, and that life on Earth may have come from other planets. [1,13]. Based on a genomic analysis, that DNA-based life has a genetic ancestry leading backwards in time over 10 billion years [8,9,10] (Joseph, Wickramasinghe, Wainwright 2011; Sharov 2009), which is twice the age of Earth.
Comet / asteroid was a source of origin of life in this planet the earth? A comet is a dirty icy snowball and much of the dirty materials are organic material formaldehyde, hydrogen and more complex substances. In cold interstellar molecular clouds gaseous species such as H2O2, CO, CO2, CH3OH, H2O and NH3 are believed to condense on to sub micron carbonaceous grain to form these icy mantes. By a combination of process that included gas grain, chemical reactions, ultraviolet photolysis and cosmic ray bombardment these components could meet further to produce small amount of complex organic compound. Icy planetismals that probably formed through successive aggregation and agglomeration of such ice-coated grain might have carried significant amount of pre-biotic organic molecules to this earth during its early history. But these organic substances must had been destroyed by the heat generated of impact as comet bombarded in the early earth? If these fragile compounds had some how survived, they could have provided the starting point for the chemical evolution that led to more complex molecules like amino acids, nucleic acids and ultimately giant molecule “The RNA or DNA’. So in that case there needed extra terrestrial source of organic compounds. Carl Sagon [Science 27th July 1990, P366] told that only small parts of comets flowing in the earth atmosphere would stay cool enough to preserve the organic chemicals. J.Mayo Greenberg was however in favoring of comet as source of compounds as origin of life in this planet the earth. According to Greenberg the Icy particles make up the comets. In his laboratory, he made icy particles that make up comets. To create them he condensed mixture of water vapor, methane, CO, and other gases present in the interstellar spaces on a glass plate cooled to~100K. The Icy was amorphous like a comet ice, having a disorderly molecular structure rather then crystalline one. Amorphous ice conducts heat more slowly then the crystalline ice. Greenberg found that when ice was deposited very slowly as it would be in the interstellar grains it’s thermal conductivity become slower and slower by a factors 10,000-100,000, because of lesser connectedness’ of water molecules that had accumulated slowly. The effect of this lower thermal conductivity might have to insulate the organic materials against the heat of a cometary’s impact. While the outer layer of grains were vaporized during the comet collision on earth atmosphere, the inner part might survived unscalled and floated gently on sea of earth. But one of the most mysterious feature of present day is the fact that ribose and deoxyribose sugar in RNA and DNA are all right handed while amino acids that make up proteins are all south. This is a puzzle because sugars and amino acids are chiral molecule i.e. they can exist in two different mirror image. But on earth they do not exist as chiral. No one could answer how this enantiomeric excess came about on earth.

So It will be highly necessary for independent experts in microbiology to determine whether the photomicrographs of microfossils in meteorites published by Hoover (2011) [7 ]are sufficiently similar in morphology to modern analogs to likely be the remains of extraterrestrial cyanobacteria and are truly biological one by microbiological DNA and rRNA tests .microstructures in carbonaceous meteorites may be obvious contaminants from modern worlds too. Just last month in the journal Nature, similar filamentous structures have been explained by non-biological processes [11] (Marshall et al., 2011). A confirmed discovery of life that has evolved outside Earth is no doubt a big step according to authors, but it is still just a beginning and hypothetical one. After that, the next big task is to learn more about life in the universe. How common is life? How diverse is it? How complex? In what sort of environmental conditions can life survive? These are big questions before us
References

1] Prof. Pranab kumar Bhattacharya; Rupak Bhattacharya, Ritwik Bhattacharya, Miss upasana Bhattacharya and Dalia Mukherjee “The Life in Our Planet the Earth” once published“ in the E book form Published at http://www.unipathos.com” in 2005 presently in2011 unipathos.com had been sold.

2] Nagy, B., Meinschein, W.G. and Hennessy, D.J. (1961) Mass spectroscopic analysis of the Orgueil meteorite: evidence for biogenic hydrocarbons. Annals of the New York Academy of Sciences 93, 25-35.

11] Marshall, C. P., Emry, J. R. & Olcott Marshall, A. (2011). Nature Geosci. advance online publication doi:10.1038/NGEO1084
12] Rupak Bhattacharya, Prof Pranab kumar Bhattacharya, Ritwik Bhattacharya, Miss Upasana Bhattacharya, Dalia Mukherjee, Aindrila Mukherjee, Soumyak Bhattacharya etal “The early earth, the evolution of the early atmosphere and life” comment# 9991 Published for the article Methane-eating microbes make their own oxygen Bacteria may have survived on Earth without plants, thanks to unique metabolism by author Amanda Leigh Mascarelli, published online on 24 March 2010 | Nature | doi:10.1038/news.2010.146
13] Rupak Bhattacharya, Prof Pranab kumar Bhattacharya, Ritwik Bhattacharya, Miss Upasana Bhattacharya, Aindrila Mukherjee, Soumyak Bhattacharya etal Theory of Pan-spermia aswell breaking the symmetry is however essential for development of life in other worlds in other universes too Published comment for the article “ Infinity Success in coping with infinity could strengthen case for multiple universes” By Tom Siegfried at Science News June 6th, 2009; Vol.175 #12 (p. 26) http://www.sciencenews.org/view/generic/id/47511/title/Comment http://nasaengineer.com/?p=2133Copy Right- Copy Right of this comment in Journal Nasaengineer. com belongs toProfessor Pranab kumar Bhattacharyaand his first degree relatives only as per copy right act & rules of Intellectual Property Right Rules 3D/107/1201 a,b/ RDF Copy Right rules/ SPARC copy Right rules-2006/ and Protect intellectual Property Right(PIP) copy right rules of USA-2012.Please do not Infringe and be enough careful for your own safety if you are not direct Blood relation to prof Pranab Kumar Bhattacharya . No person, No NGOS [ except the authors& first degree relatives] in the state of West Bengal or in any states of India or in any abroad countries are authorized to use this article, with any meaning full, scientific sentences or with scientific and meaning full words laid out in this article either in the class room/ or in mass teaching programme including CME or in any form what so ever it is with any content of this article or while in writing any book or for his/her personal/ home use, or collective works or for any future Research or implementation as a policy matter or,[ except the authors ]or by Xeroxing and distributing the article/ or by printing/saving/broadcasting the article from any website of internet services,displayed without proper copy right clearance from the authors or from his family members or future copy right owner by written forms.